root / prex-0.9.0 / usr / lib / libc / stdlib / strtol.c @ 03e9c04a
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1 | 03e9c04a | Brad Neuman | /*-
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2 | * Copyright (c) 1990, 1993
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3 | * The Regents of the University of California. All rights reserved.
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4 | *
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5 | * Redistribution and use in source and binary forms, with or without
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6 | * modification, are permitted provided that the following conditions
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7 | * are met:
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8 | * 1. Redistributions of source code must retain the above copyright
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9 | * notice, this list of conditions and the following disclaimer.
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10 | * 2. Redistributions in binary form must reproduce the above copyright
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11 | * notice, this list of conditions and the following disclaimer in the
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12 | * documentation and/or other materials provided with the distribution.
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13 | * 3. Neither the name of the University nor the names of its contributors
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14 | * may be used to endorse or promote products derived from this software
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15 | * without specific prior written permission.
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16 | *
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17 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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18 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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19 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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20 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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21 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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22 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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23 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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24 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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25 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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26 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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27 | * SUCH DAMAGE.
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28 | */
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29 | |||
30 | #include <limits.h> |
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31 | #include <ctype.h> |
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32 | #include <errno.h> |
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33 | #include <stdlib.h> |
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34 | |||
35 | |||
36 | /*
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37 | * Convert a string to a long integer.
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38 | *
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39 | * Ignores `locale' stuff. Assumes that the upper and lower case
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40 | * alphabets and digits are each contiguous.
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41 | */
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42 | long
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43 | strtol(nptr, endptr, base) |
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44 | const char *nptr; |
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45 | char **endptr;
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46 | int base;
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47 | { |
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48 | const char *s; |
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49 | long acc, cutoff;
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50 | int c;
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51 | int neg, any, cutlim;
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52 | |||
53 | /*
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54 | * Skip white space and pick up leading +/- sign if any.
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55 | * If base is 0, allow 0x for hex and 0 for octal, else
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56 | * assume decimal; if base is already 16, allow 0x.
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57 | */
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58 | s = nptr; |
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59 | do {
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60 | c = (unsigned char) *s++; |
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61 | } while (isspace(c));
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62 | if (c == '-') { |
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63 | neg = 1;
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64 | c = *s++; |
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65 | } else {
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66 | neg = 0;
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67 | if (c == '+') |
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68 | c = *s++; |
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69 | } |
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70 | if ((base == 0 || base == 16) && |
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71 | c == '0' && (*s == 'x' || *s == 'X')) { |
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72 | c = s[1];
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73 | s += 2;
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74 | base = 16;
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75 | } |
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76 | if (base == 0) |
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77 | base = c == '0' ? 8 : 10; |
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78 | |||
79 | /*
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80 | * Compute the cutoff value between legal numbers and illegal
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81 | * numbers. That is the largest legal value, divided by the
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82 | * base. An input number that is greater than this value, if
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83 | * followed by a legal input character, is too big. One that
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84 | * is equal to this value may be valid or not; the limit
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85 | * between valid and invalid numbers is then based on the last
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86 | * digit. For instance, if the range for longs is
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87 | * [-2147483648..2147483647] and the input base is 10,
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88 | * cutoff will be set to 214748364 and cutlim to either
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89 | * 7 (neg==0) or 8 (neg==1), meaning that if we have accumulated
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90 | * a value > 214748364, or equal but the next digit is > 7 (or 8),
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91 | * the number is too big, and we will return a range error.
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92 | *
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93 | * Set any if any `digits' consumed; make it negative to indicate
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94 | * overflow.
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95 | */
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96 | cutoff = neg ? LONG_MIN : LONG_MAX; |
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97 | cutlim = (int)(cutoff % base);
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98 | cutoff /= base; |
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99 | if (neg) {
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100 | if (cutlim > 0) { |
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101 | cutlim -= base; |
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102 | cutoff += 1;
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103 | } |
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104 | cutlim = -cutlim; |
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105 | } |
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106 | for (acc = 0, any = 0;; c = (unsigned char) *s++) { |
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107 | if (isdigit(c))
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108 | c -= '0';
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109 | else if (isalpha(c)) |
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110 | c -= isupper(c) ? 'A' - 10 : 'a' - 10; |
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111 | else
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112 | break;
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113 | if (c >= base)
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114 | break;
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115 | if (any < 0) |
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116 | continue;
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117 | if (neg) {
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118 | if (acc < cutoff || (acc == cutoff && c > cutlim)) {
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119 | any = -1;
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120 | acc = LONG_MIN; |
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121 | errno = ERANGE; |
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122 | } else {
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123 | any = 1;
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124 | acc *= base; |
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125 | acc -= c; |
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126 | } |
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127 | } else {
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128 | if (acc > cutoff || (acc == cutoff && c > cutlim)) {
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129 | any = -1;
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130 | acc = LONG_MAX; |
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131 | errno = ERANGE; |
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132 | } else {
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133 | any = 1;
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134 | acc *= base; |
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135 | acc += c; |
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136 | } |
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137 | } |
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138 | } |
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139 | if (endptr != 0) |
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140 | /* LINTED interface specification */
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141 | *endptr = (char *)(any ? s - 1 : nptr); |
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142 | return (acc);
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143 | } |